This invention relates to rolling devices such as roller skates, inline skates, skateboards, scooters, skis on wheels, wheel chairs, tricycles etc. Roller skates and skateboards are known which provide two non-tiltable wheel pair mechanisms, named trucks, one at each end, wherein the platform can be tilted sideways and the wheels steer responding to the tilt by making the trucks rotate, comprising inclined rotation axes, thereby influencing the direction in which the wheels are rolling. Usually cylindrical wheels are used that cause undesirably high friction. Upon tilting, the mass acceleration forces are directed off the midline of the wheels"" tracks, loading the wheels unequally and finally limiting the maximum tilt angle. In line skates, however, tilt as a whole. They are equipped with the known narrow wheels, which have little friction, but they cannot be steered by tilt.
DE19803412A1 discloses tiltable and tilt-steered wheel supports, wherein the wheels are fixed to longitudinal guides, the latter functioning as a compound guide system based on two sets of longitudinal fourfold linked chains. Any such solution using longitudinal guides is technically complex. Another problem is that such a solution causes unequal loading on the wheels of each pair.
This disadvantage has been overcome by using cross-guides. WO85/03644A1 describes wheels affixed to holders, which are guided using cross-guides in order to form a parallelogram chain having four links each. The entire system is pivotally secured to a base plate, where the pivot axis is vertically oriented with respect to this base plate, like a bogie. Steering is coupled to the tilt by using two gear wheels where one gear wheel is attached to the base plate. This solution still requires many parts and is complex.
A principal objective of the present invention is to provide a novel steering mechanism to be used in wholly tiltable rolling devices wherein the steering angle is coupled to the tilt angle in a simple and kinematically well defined manner. Another major objective of this invention is to provide a steering mechanism which distributes the radial load equally on the wheels. A further important objective of this invention is to provide a steering mechanism which uses only a few simple parts or standard components.
These advantages are attained as follows. A multi-tracked tilt-steered rolling device which incorporates pairs of tiltable wheels wherein the wheels are guided in form of a parallelogram is modified so that it comprises two cross-guides 5, 6 which are rotatably affixed to extensions 8a, 8b of the platform, their rotation axes 9a, 9b being at an angle a to the pivot axes 7a, 7b, 7c, 7d, of the parallelogram link chain. These two cross-guides 5, 6 attach pivotably to two separate wheel holders 4a, 4b where the pivot axes 7a, 7b of the first cross-guide 5 and the pivot axes 7c, 7d of the second cross-guide 6 are preferably oriented longitudinally and parallel, so that the known parallelogram link chain is formed. One wheel 3a is rotatably affixed to one wheel holder 4a and the other wheel 3b is rotatably affixed to the other wheel holder 4b. Alternatively the second cross-guide 6 is universally joined to the extension of the platform 2 using a universal joint 12. The angle xcex1 makes the rolling device capable to be steered by tilt.